Work is continuing on the study of a group of neurological mutants of Drosophila melanogaster. Some of the mutants show endogenous, spontaneous firing patterns in the indirect flight muscle system. Correlated with these firing patterns is a loss of flight. The system is being investigated to determine the genetic and physiological basis of flight. The relative sensitivity of these mutants to a range of anaesthetic agents is also under investigation. Since these mutants show a unique property when under the influence of ether, namely a vigorous leg shaking behavior, other influences of ether will be studied; the anaesthetic and killing effects. The effects of other anaesthetic agents will also be investigated.